Alkanes and Alkenes - 4 Flashcards
Are alkanes and polar or non-polar, and why
Nonpolar because carbon and hydrogen have similar electronegativities
What is the shape and bond angle of an alkane
Tetrahedral
109.5
Describe the sigma bond in an alkane
The sigma bond is a covalent bond which has a direct overlap of electrons
What type of intermolecular forces do alkanes have and why
London dispersion forces
Because bonds are non-polar
What happens to the boiling point as alkane chain length increases and why
The boiling point increases because there is a larger surface area, so more London dispersion forces, so more energy is required to overcome the attraction
How does branching affect boiling point of alkanes
Increased branching decreases boiling point, because there are fewer points of surface contact
So less London dispersion forces
So less energy needed to overcome the attractions
Are alkanes soluble or insoluble
Insoluble
What reactions do alkanes undergo
Combustion and free radical substitution
what are the 3 stages of free radical substitution
Initiation
Propagation
Termination
What bonds make up the C=c bond in alkenes
Pi and sigma bond
How is a pi bond formed
Electrons in the adjacent p-orbitals overlap above and below the carbon atoms
Which bond restricts rotation of carbon atoms
Pi bond
What is the bond angle and shape of a double bond
Trigonal Planar
120
Are alkenes more or less reactive than alkanes and why
More reactive due to high electron density of double bond and the fact the Pi bond is easier to break
What intermolecular forces do alkenes have
London dispersion forces
What is an electrophile
species that are electron pair acceptors
what conditions are needed for electrophilic addition of H20 to an alkene
Steam
Acid catalyst
What is the product of a hydration reaction
An alcohol
What conditions are needed for the electrophilic addition of a hydrogen halide to alkenes
RTP
What is the name given when a halogen reacts with an alkene
halogenation
How can a alkene be converted to an alkane
Hydrogenation
150 degrees c
nickel catalyst
What ways can plastics be disposed of
Landfill
Combustion
Reuse
Recycle
Feedstock
Disadvantages of recycling
Expensive
Labour intensive
Require high technology
How are photodegradable polymers broken down
Broken down chemically using energy with wavelengths similar to light
